Axons can be myelinated (wrapped in a myelin sheath) – allowing for faster nerve impulse conduction – or non-myelinated (without a myelin sheath). In collaboration with the research group of Professor Carmen Birchmeier, developmental biologist at the MDC, Dr. Grigoryan showed in mice how axon myelination or non-myelination is regulated in the peripheral nervous system (PNAS, doi: /10.1073/pnas.1310490110)*.
Besides neurons, glial cells are also key players in the nervous system. “Without the support of the glial cells, the nerve cells would not be able to function,” said Dr. Grigoryan. In the peripheral nervous system the Schwann cells play an important role. These are a group of glial cells named after their discoverer Theodor Schwann (1810-1882). Schwann cells surround the axons and form a myelin sheath. “Following a nerve injury in the peripheral nervous system, the Schwann cells trigger axon regeneration.” However, not all axons have a myelin sheath. How is this process regulated?
“At the beginning of their development in the embryo, the axons are grouped in bundles as extension of a nerve cell and are surrounded by a Schwann cell,” said Dr. Grigoryan. “At birth, however, the Schwann cell begins to sort out the thick axons from the bundle and to wrap them in a myelin sheath. The thin axons are not sorted out – they remain bundled and do not receive a myelin sheath. Researchers call this process axonal radial sorting.”
The large and thicker axons are wrapped by the Schwann cells in multiple layers. Due to this myelin insulation – like a power cable sheathed in plastic – these axons, for example of motor neurons, can transfer information very fast. This is why you can pull your hand quickly away from a hot stove, because the axons signal the information “hot – danger of burns”.
This fundamental process is regulated by a signaling pathway which researchers in Professor Walter Birchmeier’s laboratory have been studying for many years – the Wnt/beta-catenin signaling pathway. It is one of the best-studied signaling pathways. It plays a key role in embryonic development, cell growth (proliferation), cell maturation or cell specialization (differentiation) and in the regulation of stem cells, and, as the most recent work from the MDC now shows, even in the formation and differentiation of axons.
The research team attaches special significance to its discovery, since a dysregulation of Schwann cells can lead to a number of serious diseases. Dr. Grigoryan and her colleagues hope that this discovery will not only contribute to a better understanding of Schwann cell development but also to deeper insight into the pathogenesis of diseases in which these cells are involved.
*Wnt/Rspondin/β-catenin signals control axonal sorting and lineage progression in Schwann cell development
Tamara Grigoryana, Simone Steina, Jingjing Qia, Hagen Wendeb, Alistair N. Garrattc, Klaus-Armin Naved, Carmen Birchmeierb, and Walter Birchmeiera,1
aCancer Research Program and bNeuroscience Program, Max Delbrück Center for Molecular Medicine, 13125 Berlin, Germany; cCenter for Anatomy, Charité University Hospital, 10117 Berlin, Germany; and dDepartment of Neurogenetics, Max Planck Institute for Experimental Medicine, 37075 Göttingen, GermanyContact:
Barbara Bachtler | Max-Delbrück-Centrum
Rochester scientists discover gene controlling genetic recombination rates
23.04.2018 | University of Rochester
One step closer to reality
20.04.2018 | Max-Planck-Institut für Entwicklungsbiologie
Physicists at the Laboratory for Attosecond Physics, which is jointly run by Ludwig-Maximilians-Universität and the Max Planck Institute of Quantum Optics, have developed a high-power laser system that generates ultrashort pulses of light covering a large share of the mid-infrared spectrum. The researchers envisage a wide range of applications for the technology – in the early diagnosis of cancer, for instance.
Molecules are the building blocks of life. Like all other organisms, we are made of them. They control our biorhythm, and they can also reflect our state of...
University of Connecticut researchers have created a biodegradable composite made of silk fibers that can be used to repair broken load-bearing bones without the complications sometimes presented by other materials.
Repairing major load-bearing bones such as those in the leg can be a long and uncomfortable process.
Study published in the journal ACS Applied Materials & Interfaces is the outcome of an international effort that included teams from Dresden and Berlin in Germany, and the US.
Scientists at the Helmholtz-Zentrum Dresden-Rossendorf (HZDR) together with colleagues from the Helmholtz-Zentrum Berlin (HZB) and the University of Virginia...
Novel highly efficient and brilliant gamma-ray source: Based on model calculations, physicists of the Max PIanck Institute for Nuclear Physics in Heidelberg propose a novel method for an efficient high-brilliance gamma-ray source. A giant collimated gamma-ray pulse is generated from the interaction of a dense ultra-relativistic electron beam with a thin solid conductor. Energetic gamma-rays are copiously produced as the electron beam splits into filaments while propagating across the conductor. The resulting gamma-ray energy and flux enable novel experiments in nuclear and fundamental physics.
The typical wavelength of light interacting with an object of the microcosm scales with the size of this object. For atoms, this ranges from visible light to...
Stable joint cartilage can be produced from adult stem cells originating from bone marrow. This is made possible by inducing specific molecular processes occurring during embryonic cartilage formation, as researchers from the University and University Hospital of Basel report in the scientific journal PNAS.
Certain mesenchymal stem/stromal cells from the bone marrow of adults are considered extremely promising for skeletal tissue regeneration. These adult stem...
13.04.2018 | Event News
12.04.2018 | Event News
09.04.2018 | Event News
23.04.2018 | Physics and Astronomy
23.04.2018 | Physics and Astronomy
23.04.2018 | Trade Fair News